refinanced commercial property closing costs

[LSTAX]

When a commercial property is refinanced are the settlement fees deducted over the life of the loan or over 39 years nonresidential property.

Thank you

[abctax55]

Life of loan. 

[LSTAX]

Thank you  As a follow up, that would mean that closing fees for residential rental are life of the loan as well, and we don't use 27.5 or 39 for closing fees?  Office in home though I heard you use 39 years because the home office is non residential business property.